In electrically driven vehicles, what are referred to as traction batteries are used in order to make available energy for the drive motors. These are usually high-voltage batteries, and the batteries are composed of a plurality of battery modules which are themselves each constructed of individual battery cells. The batteries usually also contain electronics for controlling the charging and discharging and for service functions.
In, the case of defective battery cells, in the case of mechanical deformation of the battery cells or in the case of incorrect electrical connection of the battery cells, degassing of the cells may occur, and owing to the high energy density hot gases may escape and a high pressure can be produced.
For this reason, degassing elements are provided in the battery modules in order to permit pressure equalization with the surroundings and to enable the gas escaping from the battery cells to exit the battery module in a controlled fashion.
In practice it is important that the degassing element is sufficiently dimensioned so that the overall damage in the case of gas escaping is kept within limits. In order to determine a suitable geometry, it is conceivable to use a flow simulations. However, in this context assumptions have to be made with respect to the quantity of gas flowing out of the battery cell, the temperature of the gas and the composition of the gas.
US 2014 0216 139 A1, which is incorporated by reference herein, presents a test device for detecting the escaping of gas from a battery. A steel chamber and two pumps are provided, and the pressure in the steel chamber is reduced in two stages by means of the pumps. The escaping of the gas is analyzed.
WO 2011 015 554 A2, which is incorporated by reference herein, presents a detection device for a test system for testing batteries. A test chamber with an apparatus for detecting and analyzing a gas to be tested is provided.
EP 2 003 435 B1, which is incorporated by reference herein, presents a device for determining the tightness of a lithium ion cell, and the cell to be tested can be moved into an identification fluid and moved out of same by means of a lifting and lowering device within a container.
DE 10 2013 215 003 A1, which is incorporated by reference herein, shows a battery testing system for testing a battery. The battery to be tested is inserted into a testing chamber, and the testing chamber is flooded with insert gas. The inert gas can be discharged from the testing chamber again via a gas discharge device.
DE 103 01 430 A1, which is incorporated by reference herein, describes a method for testing the seal of galvanic elements. The elements are arranged in a closed container and in the case of testing are firstly subjected to an overpressure and subsequently an under pressure.